php - How to store items recursively? -

i want collect& store data array while drilling structured data, when done, have array ex::

[{nodes:[{nodes:[], id:2}, {nodes:[{nodes:[], id:4}], id:3} ], id:1}] 

notice how store deeper nodes parent nodes,here attempt simplified, tried pass node reference able collect deeper nodes parent nodes:

$parentnode= array('nodes'=>array()); scan ($parentnode, $excel, 0, 0);  function scan (& $parentnode, $excel, $row, $column, $maxcolumn) {     $childnode = array('nodes' => array(), 'id' => $excel[$row]['cr'.$column]);      // make sure drilling expected, used echo:     echo ($newnode['id'].',');     // now, push child node passed reference parent node:     array_push($parentnode['nodes'], $childnode);     // keep drilling, pass child node parent:     $this->scan($childnode, $excel, $row, $column + 1, $maxcolumn); } 

but, is:

{nodes:[{nodes:[],id:1}]} 

why wouldn't expect? long pass childnode reference, should able build pyramid of nodes based on first passed node, right?